Generally, an energy storage transmission system of a circuit-breaker spring operating mechanism is required to have a clutch device, such that when the energy storage process is completed and an energy storage shaft stops rotating, the transmission system can be automatically disengaged from the energy storage shaft by the clutch device; and when a closing spring releases energy to perform a rapid closing action to drive the energy storage shaft to rotate or when the closing action is finished and the energy storage process is performed again, the energy storage shaft can be automatically connected to the transmission system by the clutch device so as to store energy successfully.
In the conventional spring operating mechanism, there are two types of devices for realizing the above clutching function. A first type of transmission systems is provided with a one-way controllable transmission component, such as a ratchet-and-pawl mechanism, or other intermittent transmission components, a mechanism having a driving pawl capable of rotating for a full circle and a driving wheel, a one-way clutch capable of controlling the clutching action, or a mechanism having a face clutch member and a one-way clutch. In addition to a reduction transmission gear, the first type of transmission systems also requires additional one-way transmission members and requires an additional component arranged outside a space of a main transmission chain to control the clutch action. Hence, the first type of transmission systems has a complex transmission structure, a high cost, and a large size. Furthermore, since the intermittent transmission mechanism, such as the ratchet wheel, may significantly reduce the transmission efficiency, the power of a driving electric motor has to be greatly increased to complete the energy storage process in a specified allowable operating time. A second type of transmission systems only employs gears for speed-reduction transmission (a chain wheel or a worm wheel may be further used), and a clutch device is provided inside a large gear and a small gear engaged with each other in a main transmission chain. The second type of transmission systems does not include an external transmission component or clutch controlling component. Hence, the second type of transmission systems has a simple structure, a small size and dose not have the disadvantages of the first type of transmission systems.
Examples of the conventional clutch device arranged inside a large gear and a small gear are shown in FIGS. 8, 9 and 10. In FIGS. 8 and 9, a clutch device having a retractable tooth is arranged at a toothless area of the large gear, and in a closing holding position, the toothless area is facing the small gear. When the driving electric motor is powered off, the small gear may continue to rotate under the inertia and stop randomly at any position, thus if the small gear stops at a position where tooth tips of these two gears are in contact with each other, when the large gear rotates again to reengage with the small gear in the rapid closing action and the small gear is engaged with a normal tooth of the large gear, the teeth of these two gears will be stuck and the closing action cannot be achieved. However, for the clutch device having the retractable tooth, the tooth tip of the small gear is firstly brought into contact with a tooth tip of the retractable tooth, and when the large gear rotates, the retractable tooth may retract, thereby achieving the reengagement successfully. In the clutch device shown in FIG. 8, the teeth of the small gear, the teeth at two sides of the toothless area of the large gear, and the retractable tooth all have a normal tooth profile. According to analysis, if the small gear rotates under the inertia and then stops at a specific position where the toot tip of the small gear may be brought into contact with the tooth tip of the large gear when the small gear reengages with the large gear, and although the retractable tooth of the large gear which is firstly brought into contact with the small gear may retract, a frictional force between the tooth tips may drive the small gear to rotate, thus it is still possible that the tooth tip of the normal tooth of the small gear may be brought into contact with the normal tooth of the large gear behind the retractable tooth, and the gears may be stuck. The clutch device in FIG. 9 provides solutions for overcoming the above stuck problem having a small probability of occurrence. One important solution, which is significantly different from the clutch device in FIG. 8, is that, tooth tips of the small gear, a tooth tip of the retractable tooth and a tooth tip of a first fixed tooth located rearward of an additional neutral position (toothless position) at the rearward of the retractable tooth are all designed to have inclined surfaces with involute profile surfaces on both sides of the tooth intersecting with each other, thereby solving the stuck problem. A main purpose of the clutch device in FIG. 10 invented later is also to overcome the stuck problem of the clutch device in FIG. 8. In the clutch device shown in FIG. 10, the single retractable tooth in FIG. 8 is modified as a swingable tooth which is a teeth combination having two normal teeth at two sides and one toothless area at the middle, and the swingable tooth can swing inwards to achieve the reengagement. Since the clutch device shown in FIG. 10 still uses teeth of normal tooth profiles, it still has some imperfections, and a main imperfection is that the swingable tooth is subjected to a large impact force, thus special materials and manufacturing processing methods are required to make the swingable tooth, which increases the cost. Subsequently, a clutch device is provided to replace the clutch device in FIG. 10, and this clutch device is the clutch device of the first type of transmission systems having a face clutch member and a one-way clutch, this clutch device has a high reliability, but the structural complexity, the volume and the cost thereof are greatly increased. For the clutch devices in FIGS. 8, 9 and 10, when the small gear stops at some positions, in the rapid closing action for reengagement, the large gear needs to rotate idly over a large angle (approximate to one pitch or even greater than one pitch), then the retractable tooth or the swingable tooth can be brought into contact with the static small gear. In such process, the closing spring having a large power releases a large amount of energy, which generates a large impact force when the retractable tooth or the swingable tooth is brought into contact with the small gear. In each of these clutch devices, no small arc transition surface is provided at a transition area between surfaces of the tooth tip, thus the contact stress at the tooth tip is large, which requires both of the above movable teeth to have a high impact strength. If a spring operating mechanism, with a greatly increased operating power or a large operating power, employs the clutch devices described above, since the large gear rotates idly in the rapid closing action for reengagement and the energy released by the closing spring is greatly increased, the impact force on the movable tooth is greatly increased, and the requirement for the impact strength of the movable tooth is accordingly greatly increased, and may be increased to such a degree that is hard to reach. In order to enable the large gear to bear a greatly increased torque without overly increasing a diameter thereof and overly reducing a transmission ratio between the large gear and the small gear, the gear should have a large module and a large tooth width, and the number of teeth of each the large gear and the small gear has to be greatly reduced, which may further increase the idling angle of the large gear and the impact force in the rapid closing action for reengagement. Furthermore, according to diagram analysis, if the small gear has less teeth, both the clutch devices in FIGS. 8 and 10 cannot avoid the possible situation (with a small probability) that the closing action cannot be achieved since the gears are stuck.